Demystifying the Environmental Sustainability of Food Production

Co-authored with R. A. Cady and D. E. Bauman, published in the Proceedings of the Cornell Nutrition Conference 2009

The environmental impact of dairy production: 1944 compared with 2007

Co-authored with R. A. Cady and D. E. Bauman, published in the Journal of Animal Science (2009)

A common perception is that pasture based, low-input dairy systems characteristic of the 1940s were more conducive to environmental stewardship than modern milk production systems. The objective of this study was to compare the environmental impact of modern (2007) US dairy production with historical production practices as exemplified by the US dairy system in 1944. A deterministic model based on the metabolism and nutrient requirements of the dairy herd was used to estimate resource inputs and waste outputs per billion kg of milk. Both the modern and historical production systems were modeled using characteristic management practices, herd population dynamics, and production data from US dairy farms. Modern dairy practices require considerably fewer resources than dairying in 1944 with 21% of animals, 23% of feedstuffs, 35% of the water, and only 10% of the land required to produce the same 1 billion kg of milk. Waste outputs were similarly reduced, with modern dairy systems producing 24% of the manure, 43% of CH4, and 56% of N2O per billion kg of milk compared with equivalent milk from historical dairying. The carbon footprint per billion kilograms of milk produced in 2007 was 37% of equivalent milk production in 1944. To fulfill the increasing requirements of the US population for dairy products, it is essential to adopt management practices and technologies that improve productive efficiency, allowing milk production to be increased while reducing resource use and mitigating environmental impact.

The environmental impact of biotechnology: application of recombinant bovine somatotropin (rbST) in dairy production.

The environmental impact of using recombinant bovine somatotropin (rbST) in dairy production was examined on an individual cow, industry-scale adoption, and overall production system basis.  An average 2006 U.S. milk yield of 28.9 kg per day was used, with a daily response to rbST supplementation of 4.5 kg per cow.  Rations were formulated and both resource inputs (feedstuffs, fertilizers, and fuels) and waste outputs (nutrient excretion and greenhouse gas emissions) calculated. The wider environmental impact of production systems was assessed via acidification (AP), eutrophication (EP), and global warming (GWP) potentials. From a producer perspective, rbST supplementation improved individual cow production, with reductions in nutrient input and waste output per unit of milk produced. From an industry perspective, supplementing one million cows with rbST reduced feedstuff and water use, cropland area, N and P excretion, greenhouse gas emissions, and fossil fuel use compared with an equivalent milk production from unsupplemented cows. Meeting future U.S. milk requirements from cows supplemented with rbST conferred the lowest AP, EP, and GWP, with intermediate values for conventional management and the highest environmental impact resulting from organic production. Overall, rbST appears to represent a valuable management tool for use in dairy production to improve productive efficiency and to have less negative effects on the environment than conventional dairying.

The environmental impact of using recombinant bovine somatotropin (rbST) to improve the productive efficiency of one million lactating dairy cows

Co-authored with R. A. Cady and D. E. Bauman, presented as a poster at the ADSA/ASAS Annual Meeting 2008

Comparing the environmental impact of dairy production in 1944 to 2007

Co-authored with R. A. Cady and D. E. Bauman, presented at the ADSA/ASAS Annual Meeting 2008

Rumensin and milk fat depression

Co-authored with M. E. Van Amburgh, G. D. Mechor and D. E. Bauman, published in the proceedings of the Cornell Nutrition Conference, 2008

Rumensin did not induce milk fat depression in high producing lactating dairy cattle fed either high or low starch diets.  Rumensin or starch did not affect milk yield but Rumensin did have a positive effect on milk protein percent. Cattle consuming corn oil, demonstrated increased dry matter intake and milk yield but significantly reduced milk fat percent.  The combination of high starch, oil and Rumensin had a negative stepwise effect on milk fat percent demonstrating an additive effect of the treatment factors.  Milk fat levels of trans-10 C18:1 reinforced the observations that this fatty acid is a consistent marker for the extent of milk fat depression and levels were consistent with the observed concentrations of trans-10, cis-12 C18:2 known to be the primary fatty acid involved in milk fat depression.  Comparison of the milk fat content of trans-10, cis-12 C18:2 with published data and equations to predict milk fat percentages demonstrated that this fatty acid was primarily responsible for the milk fat depression observed in this study.

Increased production reduces the dairy industry’s environmental impact

Co-authored with R. A. Cady and D. E. Bauman, published in the proceedings of the Cornell Nutrition Conference, 2008

Environmental impact of rbST utilization

Co-authored with E. Castenada-Gutierrez and D. E. Bauman, published in the proceedings of the Cornell Nutrition Conference, 2007

Recent advances in the regulation of milk fat synthesis

Co-authored with K. J. Harvatine, Y. R. Bosclair and D. E. Bauman, presented at EAAP 2007

In addition to its economic value, milk fat is responsible for many of milk’s characteristics and can be markedly affected by diet. Diet-induced milk fat depression (MFD) was first described over a century ago. The biohydrogenation theory established that MFD is caused by an inhibition of mammary synthesis of milk fat by specific fatty acid intermediates of ruminal biohydrogenation. During MFD transcription of key mammary lipogenic genes are coordinately down-regulated. Our investigations have established that expression of SREBP1 and SREBP-activation proteins are down-regulated during MFD. Importantly, key lipogenic enzymes are transcriptionally regulated via SREBP1. Collectively, these results provide strong evidence for SREBP1 as a central signalling pathway in the regulation of mammary FA synthesis. Spot 14 is also down-regulated during MFD, consistent with a role for this novel nuclear protein, possibly as a lipogenic factor. In addition, knockouts of SREBP1 or Spot 14 in the mouse exhibit a milk fat reduction of similar magnitude and pattern to MFD. Knockout of lipogenic enzymes blocks milk fat production, but this appears to be related to the essentiality of the enzyme rather than a specific regulatory step. Genetic analysis has identified QTLs and SNPs that are able to explain a small portion of the variation in milk fat, but additional functional analysis will be valuable. Overall, genomic approaches continue to provide exciting insight into the regulation of milk fat synthesis.

Ruminants as animal models for nutrition research: regulation of nutrient partitioning and milk fat synthesis

Co-authored with D. E. Bauman, E. Castenada-Gutierrez and K. J. Harvartine; published in the Proceedings of Experimental Biology 2007

Effects of linolenic acid and dietary vitamin E supplementation on sustained conjugated linoleic acid production in milk fat from

Co-authored with A. M. O’Donnell, N. S. Mittelman and D. E. Bauman, presented at the ADSA/ASAS Annual Meeting 2008

Conjugated linoleic acid (cis-9, trans-11 18:2, CLA), a bioactive fatty acid (FA) found in milk and dairy products, has potential human health benefits due to its anticarcinogenic and antiatherogenic properties. Milk fat CLA concentrations can be markedly increased by dietary manipulation; however, high levels of CLA are difficult to sustain as rumen biohydrogenation shifts and milk fat depression (MFD) is induced. The objective of the present study was to feed a typical Northeastern corn based-diet and investigate whether vitamin E and soybean oil supplementation would sustain an enhanced milk fat CLA content while avoiding MFD. Holstein cows (n = 48) were assigned to a randomized complete block design for 28 d and received one of four treatments: 1) control (C), 2) 10,000 IU/d vitamin E (E), 3) 2.5% soybean oil (Oil), and 4) 10,000 IU/d vitamin E plus 2.5% soybean oil (Oil/E). A 2 wk pre-treatment control diet served as the covariate. Milk fat percent was reduced by both high oil diets (3.52, 3.55, 2.94, and 2.98% for C, E, Oil, and Oil/E, respectively). However, milk yield was increased by the Oil/E diet, therefore milk fat yield was lowest in cows fed the Oil diet (1.35, 1.35, 1.06, and 1.25 kg/d for C, E, Oil, and Oil/E). Milk protein percent was higher for cows fed the Oil diet (3.06, 3.06, 3.29 and 3.03% for C, E, Oil and Oil/E), implying that nutrient partitioning was altered in response to the reduction in milk fat. Milk fat concentration of CLA more than doubled in cows fed the oil diets, with concurrent increases in trans-10 18:1 and trans-11 18:1 FA. Moreover, milk fat from cows fed the two oil diets had 31.0% less de novo synthesized FA and 33.7% more long chain preformed FA. In conclusion, dietary supplements of soybean oil caused a reduction in milk fat percent and a shift in fatty acid composition characteristic of MFD. Dietary vitamin E did not overcome the oil-induced reduction in milk fat percent or changes in FA profile, but partially mitigated the reduction in fat yield by increasing milk yield.

Effects of dietary starch and unsaturated fat with Rumensin on milk fat depression in lactating dairy cattle

Co-authored with M. E. Van Amburgh, G. D. Mechor and D. E. Bauman, presented as a poster at the ADSA/ASAS Annual Meeting 2008

This experiment investigated the effects of starch level, polyunsaturated fatty acids (PUFA) from corn oil and Rumensin (Elanco Animal Health, Greenfield, IN), and their interactions on milk fat synthesis and fatty acid profile. Eighty Holstein cows were assigned to eight treatments within a randomized, blocked design with cross-over on oil addition. Cows were housed in tie stalls and fed ad libitum TMR for approximately 10% refusals. Each treatment consisted of three 21-day periods: in the first period a high- (267 g/kg DM) or low- (203 g/kg DM) starch TMR was fed, followed by the addition of Rumensin (13 mg/kg DM) and/or corn oil at 1.2% DM (280 to 310 g/d); this provided eight different diets formulated for an average DM intake of 22.9 kg/d in period two. In the third 21-day period, cows randomized to diets containing corn oil were switched to diets without corn oil, and vice versa. Data were analyzed using a mixed model approach and the model included period, random effects of cow and fixed effects of starch, Rumensin and oil and their
interactions. Dry matter intake and milk yield were increased (P<0.01) in cows fed diets with added corn oil. Further, the addition of corn oil was the primary dietary factor responsible for the observed milk fat depression (MFD) 3.35 versus 3.05% (P<0.004). Milk fat concentration decreased by approximately 12% with the addition of corn oil and 16% with the addition of both Rumensin and corn oil. Rumensin did not induce milk fat depression in cows fed either high or low starch diets (P>0.05), but increased milk protein concentration from 2.99 to 3.07 (P<0.03). Cows fed the high starch diets also had greater milk protein concentration and yield (P<0.04). Comparing the milk fat concentration of t-10, c-12 18:2 of cows with MFD with previously reported data and equations related to MFD, the fatty acid profiles suggest that this CLA
isomer was primarily responsible for the milk fat depression observed in this study.

The effect of supplementing pregnant ewes with marine algae or linseed on milk yield, milk composition and lamb growth rate.

Co-authored with R. G. Wilkinson, A. M. Mackenzie and L. A. Sinclair; published in the Proceedings of the British Society of Animal Science, 2006

Polyunsaturated fatty acid supplementation during pregnancy alters neonatal behaviour in sheep

Co-authored with R. G. Wilkinson, A. M. Mackenzie and L. A. Sinclair; published in 'Journal of Nutrition' 2006

The objectives of the study were to determine whether supplementation of pregnant ewes with long-chain (n-3) fatty acids present in fish oil, in combination with dietary vitamin E, would alter neonatal behavior in sheep. Twin- (n ¼ 36) and triplet- (n ¼ 12) bearing ewes were allocated at d 103 of gestation to 1 of 4 dietary treatments containing 1 of 2 fat sources [Megalac, a calcium soap of palm fatty acid distillate or a fish oil mixture, high in 20:5(n-3) and 22:6(n-3)] and 1 of 2 dietary vitamin E concentrations (50 or 500 mg/kg) in a 2 3 2 factorial design. Feeding fish oil increased gestation length by 2 d and increased the proportion of 22:6(n-3) within neonatal
plasma by 5.1-fold and brain by 10%, whereas brain 20:5(n-3) was increased 5-fold. Supranutritional dietary vitamin E concentrations decreased the latency of lambs to stand in ewes fed fish oil but not Megalac, whereas latency to suckle was decreased from 43 to 34 min by fish oil supplementation. Supplementation with fish oil also substantially decreased the secretion rate (mL/h) of colostrum and the yield (g/h) of fat and protein. We conclude that supplementation of ewes with fish oil decreases the latency to suckle, increases gestation length and the 22:6(n-3):20:4(n-6) ratio in the neonatal brain, and may improve lamb survival rate. However, further work is required to determine how to mitigate the negative effects of fish oil on colostrum production.

The effect of long-chain polyunsaturated fatty acid and vitamin E supplementation of ewes on neonatal lamb vigour.

Co-authored with R. G. Wilkinson, S. E. Pattinson, A. M. Mackenzie and L. A. Sinclair; presented at ADSA/ASAS 2004

The effect of dietary vitamin E and fatty acid supplementation of pregnant and lactating ewes on placental and mammary transfer of vitamin E to the lamb

Co-authored with R. G. Wilkinson, E. Kasapidou, S. E. Pattinson, A. M. Mackenzie and L. A. Sinclair; published in 'British Journal of Nutrition' 2005

The present study investigated the effect of maternal vitamin E and fatty acid supplementation on lamb antioxidant status. Forty-eight ewes were fed one of four concentrate diets supplemented with a basal (50 mg/kg) or supranutritional (500 mg/kg) level of vitamin E plus a source of either saturated fat (Megalac; Volac Ltd, Royston, Hertfordshire, UK) or long-chain PUFA (fish oil) from 6 weeks prepartum until 4 weeks postpartum. Blood samples were taken from ewes and lambs at intervals throughout the experiment and, at parturition, muscle, brain and blood samples were obtained from twelve lambs (three per treatment). Colostrum and milk samples were obtained at 12 h and 21 d after parturition, respectively. Supranutritional vitamin E supplementation of the ewe significantly increased concentrations of vitamin E in neonatal lamb tissues although plasma concentrations were undetectable. A significant increase in lamb birth weight resulted from increasing the dietary vitamin E supply to the ewe. Furthermore, maternal plasma, colostrum and milk vitamin E concentrations were increased by vitamin E supplementation, as were lamb plasma concentrations at 14 d of age. Neonatal vitamin E status was not significantly affected by fat source although plasma vitamin E concentrations in both ewes and suckling lambs were reduced by fish oil supplementation of the ewe. Fish oil supplementation reduced vitamin E concentrations in colostrum and milk and the activity of glutathione peroxidase in suckling lambs. The data suggest that the vitamin E status of the neonatal and suckling lamb may be manipulated by vitamin E supplementation of the ewe during pregnancy and lactation.

The effect of fish oil supplementation of pregnant and lactating ewes on milk production and lamb performance

Co-authored with R. G. Wilkinson, A. M. Mackenzie and L. A. Sinclair; published in 'Animal' 2007

Supplementation of pregnant ewes with long-chain n-3 polyunsaturated fatty acids (PUFA) demonstrably improves indicators of neonatal lamb vigour, potentially improving the number of lambs reared per ewe. The present study investigated the effect of supplementing ewes with fish oil and vitamin E (a-tocopherol acetate) throughout both pregnancy and lactation on the performance of lactating ewes and sucking lambs. Forty-eight ewes were supplemented with one of four concentrates containing either Megalac or fish oil plus a basal (50 mg/kg) or supranutritional (500 mg/kg) concentration of vitamin E from 6 weeks pre-partum until 4 weeks post partum in a two-by-two factorial randomised-block design. All concentrates were formulated to contain approximately 60 g/kg supplemental fatty acids. Ewes were housed, penned on sawdust and offered straw ad libitum. Blood samples were taken from ewes and lambs at intervals throughout the experiment and milk samples were obtained at 21 days into lactation. There was no notable effect of dietary vitamin E concentration upon ewe or lamb performance. Ewe dry-matter (DM) intake and yield were unaffected by dietary treatment, although ewes fed fish oil lost less weight during lactation (21.88 kg compared with 23.97 kg for Megalac-supplemented ewes; P,0.01). Milk fat concentrations (67.3 g/kg compared with 91.8 g/kg; P,0.01) and yields (6.65 g/h v. 9.26 g/h; P,0.01) were reduced in ewes fed fish oil and these decreases were associated with lower litter-growth rates (0.49 g/day compared with 0.54 g/day; P,0.05). Milk protein yield was increased by fish oil supplementation (3.82 g/h) compared with Megalac supplementation (3.28 g/h; P,0.05);
moreover, there was an interaction between fat source and vitamin E concentration in that both protein concentration and yield were significantly lower in milk from ewes fed treatment with Megalac and basal vitamin E (MB) compared with the other three treatments. Fish oil supplementation increased the concentrations of C18:1 trans-, cis-9, trans-11 conjugated linoleic acid (CLA), C20:5 (n-3) and C22:6 (n-3) within ewe plasma, milk and lamb plasma. The mechanisms by which fish oil supplementation affects milk composition warrants further investigation.

The effect of long-chain polyunsaturated fatty acid and vitamin E supplementation of ewes on neonatal lamb vigour, lamb growth and colostrum parameters

Co-authored with R. G. Wilkinson, S. E. Pattinson, A. M. Mackenzie and L. A. Sinclair; published in the Proceedings of the British Society of Animal Science, 2002

The effect of long-chain polyunsaturated fatty acid and vitamin E supplementation of pregnant ewes on neonatal lamb behaviour and lamb growth

Co-authored with R. G. Wilkinson, S. E. Pattinson, A. M. Mackenzie and L. A. Sinclair; published in the Proceedings of the British Society of Animal Science, 2004

The effect of vitamin E and long-chain polyunsaturated fatty acid supplementation of pregnant and lactating ewes on the transfer of vitamin E to the lamb

Co-authored with R. G. Wilkinson, E. Kasapidou, S. E. Pattinson, A. M. Mackenzie and L. A. Sinclair; published in the Proceedings of the British Society of Animal Science, 2003